Patents by Inventor Akira Furukawa
Akira Furukawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 10797620Abstract: A control unit includes: control command generation means for generating a first control command and a second control command that specifies currents to flow through a first winding set and second winding set respectively; voltage calculation means for calculating a first voltage command from the first control command and calculating a second voltage command from the second control command; and first voltage application means and second voltage application means for applying voltages to the first winding set and the second winding set of a rotating machine on the basis of the first voltage command and the second voltage command, wherein discharge control for electric charge of a smoothing capacitor is performed while torque generated by current flowing from the smoothing capacitor to the first winding set and torque generated by current flowing from the capacitor to the second winding set are cancelled out with each other.Type: GrantFiled: August 24, 2016Date of Patent: October 6, 2020Assignee: Mitsubishi Electric CorporationInventors: Akira Furukawa, Munenori Yamamoto
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Patent number: 10788319Abstract: Provided is an angle detection device including: a correction signal calculator configured to generate corrected signals from a sine signal and a cosine signal acquired from an angle detector; and an angle calculator configured to calculate an angle signal for a rotary machine from the corrected signals. When one of the sine signal and the cosine signal is defined as a first detection signal, and another one thereof is defined as a second detection signal, the correction signal calculator calculates a corrected first detection signal and a corrected second detection signal, and the angle calculator calculates the angle signal for the rotary machine from the corrected first detection signal and the corrected second detection signal.Type: GrantFiled: October 3, 2016Date of Patent: September 29, 2020Assignee: Mitsubishi Electric CorporationInventors: Akira Furukawa, Wataru Ozaki, Yu Kawano
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Publication number: 20200300601Abstract: An angle detection device including: an angle sensor AGSE outputting first and second sine wave signals SINWS1, SINWS2 having phases that are different from each other by 90 degrees in accordance with rotation of a detection target; an angle calculator calculating an angle signal corresponding to a rotation angle of the detection target based on SINWS1 and SINWS2; and an angle sensor AGSE abnormality determiner ASAD determining an abnormality of AGSE based on SINWS1 and SINWS2. The ASAD includes: an amplitude signal calculator calculating an amplitude signal MALS based on a square root of a sum of squares of SINWS1 and SINWS2; a first angle signal ANGS1 calculation processor calculating ANGS1 based on SINWS1 and MALS; a second angle signal ANGS2 calculation processor calculating ANGS2 based on SINWS2 and MALS; and an abnormality determination processor determining the abnormality of AGSE based on an error between ANGS1 and ANGS2.Type: ApplicationFiled: April 28, 2016Publication date: September 24, 2020Applicant: Mitsubishi Electric CorporationInventors: Tatsuya MORI, Isao KEZOBO, Munenori YAMAMOTO, Akira FURUKAWA
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Publication number: 20200300671Abstract: Provided are a failure determination device and method for a rotating machine control device, which are capable of detecting failure of a sensor configured to detect a rotational position of a rotating machine while the rotating machine is in operation. A rotation angle estimator calculates a rotation angle estimation value. A relationship between the rotation angle estimation value (?est), and a first angle detection value (?1) and a second angle detection value (?2), which are obtained from output signals of angle sensors configured to detect a rotational position of a rotating machine, is monitored while the rotating machine is in operation. In this manner, failure of the angle sensors, which are configured to detect the rotational position of the rotating machine, can be always detected even while the rotating machine is in operation.Type: ApplicationFiled: April 28, 2016Publication date: September 24, 2020Applicant: Mitsubishi Electric CorporationInventors: Tatsuya MORI, Isao KEZOBO, Munenori YAMAMOTO, Akira FURUKAWA
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Publication number: 20200255067Abstract: To provide a motor controller and an electric power steering apparatus which can suppress torque fluctuation resulting from low detection resolution of angle, with simple calculation, even in condition where the rotational speed of motor is low. A motor controller estimates an angle error correlation value correlated with the angle detection error based on the current command value when a change frequency of the angle detection value is lower than a cutoff frequency of feedback control system which controls a rotation state; corrects the current command value or the angle detection value based on the estimation value of angle error correlation value; and changes the estimation value of angle error correlation value so that the absolute value of angle detection error increases with respect to increase in the current command value, and the absolute value of angle detection error decreases with respect to decrease in the current command value.Type: ApplicationFiled: November 7, 2017Publication date: August 13, 2020Applicant: Mitsubishi Electric CorporationInventors: Kenta TANAKA, Isao KEZOBO, Akira FURUKAWA, Seiji SAWADA
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Patent number: 10720873Abstract: Provided is an electric drive device which controls a current supplied to coils during normal operation so as to be less than a current limit value when normal, which is determined from heat generating properties and heat radiating properties of a thermally coupled body that includes the coils and an inverter circuit. When an abnormality in each group or each phase of the coils and the inverter circuit is detected, the supply of current to all phases of a group suffering an abnormality in the coils, or to a phase that is not capable of continuous operation, is stopped or reduced; and the limit value of the current supplied to a coil that is capable of continuous operation is reset to a current limit value in the event of abnormality, which is larger than the current limit value when normal, within the range of improvement of the heat generating properties of the thermally coupled body due to the stopping or reduction of the supply of current.Type: GrantFiled: February 23, 2015Date of Patent: July 21, 2020Assignee: Mitsubishi Electric CorporationInventors: Akira Furukawa, Yu Kawano
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Publication number: 20200220488Abstract: A power conversion device including: a first and second multi-phase inverters (MPI1,MPI2) to receive a DC voltage (Vdc) and convert into AC voltages (Vacs), when fc represents a frequency of a PWM signal output from each of the MPI1 and the MPI2, fr represents a lower limit frequency defined by noise regulation of the power conversion device, an absolute value of a differential voltage being a difference between: a first average voltage, which is an average value of first voltage commands of respective phases as command values for the Vacs of MPI1; and a second average voltage, which is an average value of second voltage commands of respective phases as command values for the Vacs of MPI2, is set equal to or less than k2·fc/fr·Vdc [V] (k2 is an odd number equal to or more than one), to reduce noise in a frequency band defined by noise regulation.Type: ApplicationFiled: July 3, 2017Publication date: July 9, 2020Applicant: Mitsubishi Electric CorporationInventors: Tatsuya MORI, Akira FURUKAWA
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Publication number: 20200177102Abstract: A power conversion device is configured to output, to each of two inverters configured to invert a DC voltage output from a DC power supply to three-phase AC voltages, on/off signals for switching on and off respective semiconductor switching elements of each of the inverters so that, out of a plurality of voltage vectors defined so as to correspond to patterns of the on/off signals, the second closest voltage vector and the third closest voltage vector in phase to a voltage command vector that is based on a voltage command value calculated for each of the inverters are formed.Type: ApplicationFiled: August 21, 2017Publication date: June 4, 2020Applicant: Mitsubishi Electric CorporationInventors: Tatsuya MORI, Akira FURUKAWA
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Patent number: 10666169Abstract: A control device for an AC rotary machine includes an AC rotary machine having m sets of n-phase windings, a current detector, a power converter, and a control unit that calculates voltage commands on the basis of respective differences between a current command for the AC rotary machine and current detection values obtained by the current detector, and outputs ON/OFF signals to high potential side switching elements and low potential side switching elements of the power converter by comparing applied voltages calculated on the basis of the voltage commands with a carrier wave signal, wherein the current detector, when detecting currents flowing through the n-phase windings on the basis of currents flowing through current detection resistance elements that are inserted in series into the low potential side switching elements, obtains current detection values at two or more fixed timings over a single period of the carrier wave signal.Type: GrantFiled: March 12, 2015Date of Patent: May 26, 2020Assignee: Mitsubishi Electric CorporationInventor: Akira Furukawa
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Patent number: 10666163Abstract: Voltage commands of respective phases are substantially equally shifted in such a way that a maximum-phase voltage command coincides with the maximum value of a PWM carrier signal and are compared with the PWM carrier signal, so that a voltage is controlled; in addition to that, a current detection value corresponding to the phase where the lower-arm switching device is turned on is corrected based on a current detection value corresponding to the phase where the upper-arm switching device is turned on.Type: GrantFiled: June 22, 2016Date of Patent: May 26, 2020Assignee: Mitsubishi Electric CorporationInventors: Tatsuya Mori, Akira Furukawa
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Failure determination device for angle detector of rotating machine and failure determination method
Patent number: 10666170Abstract: A failure determination device for an angle detector for a rotating machine, including: an angle detector, which includes n pole pairs (n>m), and outputs sine and cosine wave-signals in accordance with a rotational position of a rotating machine including a multi-phase winding and m pole pairs (m?2); and a failure determiner for detecting failure of the detector based on signals from the detector. The detector outputs first and second sine-wave-signals having 180° phases different, and first and second cosine-wave-signals having 180° phases different. The failure determiner determines malfunction of the detector when the failure is determined with use of at least one of: failure determination using a sum of the first and second sine-wave-signals and a sum of the first and second cosine-wave-signals; or failure determination using a sum of squares or a square root of a sum of squares of the sine-wave-signal and the cosine-wave-signal.Type: GrantFiled: April 28, 2016Date of Patent: May 26, 2020Assignee: Mitsubishi Electric CorporationInventors: Akira Furukawa, Yu Kawano, Munenori Yamamoto -
Publication number: 20200153375Abstract: An inverter device includes: an inverter, a power supply current detection sensor, a phase current detection sensor, a three-phase voltage command calculator, and an inverter on/off signal generation unit. The phase current detection sensor detects a phase current in one phase of the inverter. The inverter on/off signal generation unit generates on/off signals based on the phase voltage commands. The three-phase voltage command calculator uses the power supply current and the phase current detected by the power supply current detection sensor and the phase current detection sensor, respectively, so as to calculate phase voltage commands directed to the inverter, and at a center time point of a period in which an upper arm switching element corresponding to one phase out of two phases for which the phase current detection sensor is not provided is on, and lower arm switching elements corresponding to the other two phases are on.Type: ApplicationFiled: July 4, 2017Publication date: May 14, 2020Applicant: Mitsubishi Electric CorporationInventors: Tatsuya MORI, Akira FURUKAWA, Isao KEZOBO
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Patent number: 10611400Abstract: Provided is an electric power steering device capable of continuing control while ensuring a satisfactory level of a steering feeling of a driver at a time of occurrence of failure of one motor winding set. A control part is configured to detect a failure of each component of the electric power steering device, and when control is continued with field-weakening control by a normal motor winding and an inverter circuit depending on the detected failure, restrict a d-axis current based on a torque ripple that occurs in a steering wheel of a vehicle with respect to the field-weakening control of a state in which the failure has not occurred.Type: GrantFiled: November 2, 2015Date of Patent: April 7, 2020Assignee: Mitsubishi Electric CorporationInventors: Akira Furukawa, Yu Kawano
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Patent number: 10608568Abstract: In a control device for an AC rotary machine, having an angle detector for detecting an electrical angle of the AC rotary machine, a detection error produced by the angle detector due to a noise magnetic field generated by a multi-phase alternating current flowing through an inverter connection unit is corrected using a correction signal having a phase and an amplitude that are determined in accordance with a relative positional relationship between the inverter connection unit and the angle detector and a current vector of the multi-phase alternating current, whereupon an inverter is controlled on the basis of the corrected electrical angle. As a result, a simple, low-cost control device for an AC rotary machine with which an angular position of a rotor can be detected with a high degree of precision is obtained.Type: GrantFiled: January 23, 2015Date of Patent: March 31, 2020Assignee: Mitsubishi Electric CorporationInventor: Akira Furukawa
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Patent number: 10584953Abstract: There are arranged a sensor magnet fixed to a rotary shaft and configured to generate a magnetic field for detecting a rotation angle, and a plurality of sensors arranged so as to be opposed to the sensor magnet and each configured to output a sine signal and a cosine signal in accordance with the magnetic field. First and second sensors are arranged on two radial lines different from each other, respectively, out of three radial lines dividing a circumference about the rotary shaft of the sensor magnet into six equal parts. An angle calculation unit is configured to carry out calculation so that 3n-th (n is a natural number) order harmonic components out of odd-order harmonic components of each of the sine signal and the cosine signal output by the first and second sensors cancel one another, to thereby calculate the rotation angle.Type: GrantFiled: November 26, 2015Date of Patent: March 10, 2020Assignee: Mitsubishi Electric CorporationInventors: Akira Furukawa, Wakaki Miyaji, Yu Kawano
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Publication number: 20200062297Abstract: An electric power steering apparatus including: a steering torque detector to detect a steering torque of a driver; a motor to assist a steering force of the driver; an estimated speed calculator to calculate an estimated speed, which is an estimated value of a rotation speed of the motor; an estimated speed corrector to correct the estimated speed based on the steering torque; an estimated angle calculator to calculate an estimated angle of the motor by integrating the estimated speed after the correction; and an electric power supply to supply electric power to the motor based on the estimated angle, wherein the estimated speed corrector corrects the estimated speed when a determination signal, which is based on a value obtained by removing a frequency component of steering of the driver from a derivative of the steering torque, the steering torque, and the estimated speed have the same signs.Type: ApplicationFiled: May 18, 2017Publication date: February 27, 2020Applicant: Mitsubishi Electric CorporationInventors: Yuya TSUCHIMOTO, Isao KEZOBO, Akira FURUKAWA, Yuji TAKATSUKA
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Patent number: 10566920Abstract: A control device for an AC rotary machine includes an AC rotary machine having x-phase windings where x is at least three, an angle detector, a current detector, a voltage command calculator, and a power converter, wherein, when a current of at least one phase of the x phases is detectable and currents of at most (x?1) phases are undetectable at a present current detection timing, the current detector estimates the currents of the (x?1) phases that are undetectable at the present current detection timing by calculation on the basis of detected currents of x phases obtained at a past current detection timing, the detected current of the single phase that is detectable at the present current detection timing, and an angle variation amount from the past current detection timing to the present current detection timing.Type: GrantFiled: March 12, 2015Date of Patent: February 18, 2020Assignee: Mitsubishi Electric CorporationInventor: Akira Furukawa
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Publication number: 20200031385Abstract: There is provided an electric power steering device, including: a reverse steering detection unit configured to determine start of reverse steering when a magnitude of a rotational speed of a motor is equal to or smaller than a set speed, a rotational acceleration of the motor is in a direction of causing the rotational speed of the motor to become 0, and a magnitude of the rotational acceleration of the motor is equal to or larger than a set acceleration; and a current command control unit configured to output a current command for the motor based on the steering torque or the rotational speed of the motor, in which the current command control unit is configured to increase a transfer gain from input to output by the current command control unit when the reverse steering detection unit determines start of the reverse steering.Type: ApplicationFiled: March 27, 2017Publication date: January 30, 2020Applicant: Mitsubishi Electric CorporationInventors: Isao KEZOBO, Kenta TANAKA, Akira FURUKAWA, Masaharu TANAKA, Akiyoshi TAKASHIMA
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Patent number: 10526007Abstract: Provided is a power conversion device for suppressing a variation amount of a bus current to decrease a power loss in consideration of control of detecting the bus current during operation. In control by a power conversion part in accordance with a switching signal, a voltage vector is caused to bring a mode into a power running mode at a timing of detecting the bus current when an AC rotating machine is in a power running operation state, and the voltage vector is caused to bring the mode into a regeneration mode at a timing of detecting the bus current when the AC rotating machine is in a regeneration operation state, thereby decreasing the power loss due to the variation in the bus current.Type: GrantFiled: October 8, 2014Date of Patent: January 7, 2020Assignee: Mitsubishi Electric CorporationInventors: Akira Furukawa, Tatsuya Mori
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Publication number: 20190389506Abstract: An electric power steering apparatus includes: a torque sensor configured to detect a steering torque of a driver; a motor configured to assist in a steering force of the driver; a rotation angle estimation unit configured to estimate a rotation angle of the motor to output an estimated angle; a correction signal calculation unit configured to calculate a correction signal based on the steering torque; a frequency separation unit configured to separate the estimated angle into a first frequency component and a second frequency component; an estimated angle correction unit configured to calculate, as a control angle, a value obtained by adding a second-frequency-component corrected signal, which is obtained by correcting the second frequency component based on the correction signal, to the first frequency component; and an electric power supply unit configured to supply electric power to the motor based on the control angle.Type: ApplicationFiled: March 7, 2017Publication date: December 26, 2019Applicant: Mitsubishi Electric CorporationInventors: Yuya TSUCHIMOTO, Isao KEZOBO, Yuji TAKATSUKA, Akira FURUKAWA